Mobile hand-held unit comprising a reusable biosensor

ABSTRACT

Mobile hand-held equipment with reusable biosensor, in particular for the local determination of original biological solutions, marked by a functional wheel with valve and pump function, an amperometric biosensor, a measuring cell, supply and waste bags for fresh and waste system solution, a pump, a hose transport system, a sample opening and a sample canal, a sealing lever for sensor exchange, a display, operating elements, a 9 V accumulator, a solar cell, a control unit for signal processing and the whole measuring process and a case.

[0001] The invention concerns a hand-held equipment for the examination of biological liquids such as whole blood, liquor, urine and serum by electrochemical biosensors without costly preceding analysis being carried out.

[0002] For a fairly long time biosensors have been applied as sensitive and selective detection methods in analyses, in particular of medical diagnostics. For this purpose, respective biosensors are installed in analysers which allow to carry out a fast, inexpensive and notably proper examination of the respective parameters in central laboratories where many samples have to be examined. This requires, as a rule, a sample throughput of 80-180/h.

[0003] The analysers are based on various principles. For the most part, they are operated with a continuous air segmented flow of the respective, highly diluted laboratory samples, i.e. this method requires the preparation of the solutions to be examined (e.g. whole blood) with a dilution of the analysis material being required. It is very costly to analyse individual samples by means of this equipment as the efficiency of analysers becomes effective only in the case of a high number of samples being examined (ESAT® 6660 and ECA 180 from Prüfgeräte-Werk Medingen GmbH, EBIO (Eppendorf® from Eppendorf-Netheler-Hinz GmbH).

[0004] Furthermore, there are instructions known to measure individual samples also without preceding analyses being carried out which, however, are very immovable owing to a high integrated measuring comfort, thus being unsuited for a local application (YSI 2300 STAT of YSI Incorporated and STAT Profile PLUS of NOVA BIOMEDICAL GmbH).

[0005] For the time being, commercialized mobile systems with integrated biosensors are too expensive owing to the high measuring comfort (internal calibration), require too much maintenance and are operated with too long transport ways for the sample to be measured. For this reason, in addition to a comparatively high price, delays and pollution will result which have detrimental effects on the quality of analysing.

[0006] All measuring systems applied locally to determine parameters such as glucose and lactate are at present based on non-reusable consumables (test strips, photometric; strip electrode, amperometric). Thus the analysis is determined by the price of the test strip and the test strip is not calibratable as it may be used just once.

[0007] The ‘mobile hand-held device with biosensor’ of GM 29511566.1 represents a significant improvement. That instrument is based on a reusable biosensor allowing the calibration of the sensor resulting in an improved quality of analysis as compared to the disposable test strips. Further advantages result from lower costs of the analysis.

[0008] As compared to the high quality results of laboratory analysis the mobile hand-held device of DE 29511566.1 is characterized by mobility and constant quality, i.e., decentral analysis of high quality is possible independent from laboratory applying this instrument.

[0009] However, the technical realization of the measuring procedure has been arised to be disadvantageous during the practical use. The operation of two different operation elements in parallel is complicated and may cause handling errors.

[0010] That is why it was the task of the invention to provide a technical solution for implementing a locally applicable equipment for the examination of blood, urine, liquor without preceding analyses being carried out and a re-usable biosensor which is marked by a high quality of analysis, a low price and a simple operation procedure.

[0011] The task will be solved by the construction of a hand-held equipment with linear operation.

[0012] The hand-held equipment consists of a functional wheel with valve and pump function, an exchangeable electrochemical biosensor, a system solution supply bag, a waste bag, a pump, a hose transport system, , four operating elements, a display and a control unit for signal recording and the whole process that is supplied by a solar cell and a 9 V accumulator. The equipment works with a temperature compensation. Thus, modified sensitivities of the biosensor are compensated through variations of the ambient temperature in the range between 15° C. and 35° C. on the basis of a signal-temperature function.

[0013] Welded PE foils are preferentially used for the system solution bag and the waste bag, with the storage volume totalling approx. ⅓ and the waste volume approx. ⅔ of the total volume. The bags are opened when being installed the hand-held equipment through a hollow needle. When putting in a new supply bag the second half of the PE bag will be empty. In the same way as the stock will be consumed for rinsing the measuring cell the waste bag will be filled. After having consumed the system solution completely the whole bag will be disposed.

[0014] The easy exchangeable electrochemical biosensor is a Pt—Ag/AgCl electrode which may register various substances in accordance with the biomolecule used.

[0015] To execute a measurement the functional wheel will be moved from idle position A (5) (READY) to position B (6) (SAMPLE) by moving the wheel clockwise, thus bringing the system into the state ‘ready for measurement’.

[0016] The sample to be analysed will be supplied with adjusting the freshly taken sample in a capillary tube to the sample opening of the hand-held equipment which is directly above the biosensor. Subsequently the functional wheel is moved to position C (7) (BUSY) and the sample to be measured is transported by it in front of the biosensor. After the measurement took place the operator by the display reading is requested to take off the capillary tube and to rinse the system. The capillary tube is taken off by the operator. By moving the functional wheel to position A the sensor is rinsed and the measuring value is indicated. The measuring value will be shown in the display up to the next measurement. The reading “READY FOR USE” is regarded to be a confirmation that the rinsing is completed and the device again is ready for use.

[0017] A hose pump is preferentially used as pump which is driven by hand or electric energy.

[0018] The four operating elements will be responsible for the following functions:

[0019] B1: on

[0020] B2: menu functions

[0021] B3: set key

[0022] B4: enter key

[0023] Power supply will be realized by an internal 9 V accumulator that will be recharged preferably by a solar cell or alternatively by a supply unit.

[0024] Depending on the biomolecule used a biosensor has a limited lifetime which totals, in general, 10 to 30 days. The user will be shown the expiry of lifetime on the display. Upon expiry of its service life the biosensor will be replaced by a new one.

[0025] The biosensor is replaced by unlocking the respective sealing lever (9), taking off the worn-out biosensor (11) and simply placing a new biosensor. By the information on the display the user will be informed on the steps necessary to take until the new biosensor will be operative.

[0026] Signal recording and the whole process are controlled through a control unit. The whole process involves the beginning of signal recording (start), the end of signal recording, filing and storing of measured values, the calibration of the equipment and display information for the operator as regards the steps.

[0027] The hand-held equipment in conformity with the invention allows to carry out a minimum of 500 measurements without replacing the supply bag. A special advantage is that the equipment is usable in a temperature range between 15° C. and 35° C., independent of its place and time of use.

[0028] The invention is explained in greater detail by means of the following examples of execution and drawings.

[0029]FIG. 1—Overall view of the hand-held equipment

[0030]FIG. 2—Basic diagram of the equipment and arrangement of the supply and waste bag

[0031] The hand-held equipment in conformity with FIG. 1 serves the examination of whole blood, liquor, tissue fluid, urine, serum, plasma, food samples as well as water samples as regards metabolites such as e.g. glucose, lactate; yet also nutrients and products of food and fermentation industries such as e.g. lactose, ascorbic acid, malic acid and various amino acids.

[0032] In FIGS. 1 and 2 the structure of such an instrument is demonstrated in principle. The process of a measurement is described in the following. The idle and stand-by position of the instrument is position A (5) (READY) of the functional wheel (8). After switching on the instrument by B1 (12) the functional wheel (8) is moved to position B (6). After the operator is requested by the display (1) to place the sample into the instrument, the operator is placing the sample using a capillary tube into the sample opening (20) of the hand-held equipment and moves the functional wheel (8) to position C (7).

[0033] After completing measurement the operator is requested to take away the capillary and to rinse the system. For that purpose the capillary is taken out from the sample opening (20) and the functional wheel (8) is moved to position A (5). By that procedure I) the measured value will be shown on the display (1) and II) systemic solution is moved from the buffer supply (19) via the valve system through the sensor containing measuring chamber into the waste bag (18). The contact of the biosensor with the buffer solution results in the rinsing of the sensor. The operator is informed on the termination of the rinsing procedure by “ready for use” on display (1). Thus, the hand-held equipment will be again ready for measuring and the following measurement will be effected according to the same scheme.

[0034] The biosensor (11) is exchanged after expiry of its lifetime (which is shown the operator on display 1). To this end, the sealing lever (9) has to be opened and the old sensor will be exchanged. After that the sealing lever (9) and by that the flow system is closed again. By the information on the display the user will be informed on the steps necessary to take until the new biosensor will be operative.

[0035] Reference marks:

[0036]1 display

[0037]2 control unit

[0038]3 solar cell

[0039]4 pump

[0040]5 position A of the functional wheel

[0041]6 position B of the functional wheel

[0042]7 position C of the functional wheel

[0043]8 functional wheel

[0044]9 sealing lever

[0045]10 valve

[0046]11 biosensor

[0047]12 operating element B1

[0048]13 operating element B2

[0049]14 operating element B3

[0050]15 operating element B4

[0051]16 case

[0052]17 spring for sealing lever

[0053]18 waste bag

[0054]19 supply bag

[0055]20 sample opening

[0056]21 cover

[0057]22 seal for waste bag

[0058]23 seal for supply bag 

1. Mobile hand-held equipment with reusable biosensor, in particular for the local determination of original biological solutions, marked by a functional wheel with valve and pump function (8), an amperometric biosensor (11), a measuring cell, supply (19) and waste bags (18) for fresh and waste system solution a pump (4), a hose transport system, a sample opening (20) and a sample canal, a sealing lever for sensor exchange (9), a display (1), 4 operating elements (12, 13, 14, 15), a 9 V accumulator, a solar cell (3), a control unit for signal processing and the whole measuring process (2) and a case (16).
 2. Mobile hand-held equipment according to claim 1, marked by the fact that the biosensor (11) is arranged directly below the sample opening (20).
 3. Mobile hand-held equipment according to claims 1 and 2, marked by the fact that the pump used (4) is operated by hand or by electric energy.
 4. Mobile hand-held equipment according to claims 1-3, marked by the fact that welded PE foil is used for the supply (19) and the respective waste bags (18), the two bags are welded with each other, arranged one above the other and will be jointly disposed after the buffer stock will have been consumed.
 5. Mobile hand-held equipment according to claims 1-4, marked by the fact that the power supply of the electrode may be effected through a chargeable accumulator recharged by a solar cell (3) or by a supply unit.
 6. Mobile hand-held equipment according to claims 1-5 marked by the fact that the weight of the equipment is less than 500 g. 